Electric fire-alarm.



J. CASS.

ELECTRIC FIRE ALARM. APPLIoATIoN FILED AUG. 28, 1909.

l 1,0()3173, Patented Sept. 12, 1 911.

F/GJ. y No.9.

IIHI

COLUMBIA FLANOGRAIH co.. WASHINGTON, n, c,

UNITED STATES PATENT OFFICE.

JACOB CASS, OF MANCHESTER, ENGLAND.

ELECTRIC FIRE-ALARM.

To all whom it may concern:

Be it known that I, JACOB CAss, a subject of the Emperor of Russia, and resident of Manchester, in the county of Lancaster, in the Kingdom of Great Britain, have invented certain new and useful Improvements in Electric Fire-Alarms, of which the following is a specication.

This invention relates to the kind of electric lire alarms for rooms in buildings, in which the circuit is closed by thermostatic means.

According to this invention I use the solid transparent substance containing gelatin and made in sheets commercially known as gelat-in, as the means by which the rise in temperature effects the closing of the circuit.

On the drawing appended hereunto the improved fire alarm is represented in one form of construction as an example hcw the invention may be carried out.

Figure 1 represents a vertical section of the alarm, Fig. 2 a view of the top as seen from below, Fig. 3 a horizontal section along line a; o@ and Fig. 4 a section along line g/ y, Fig. 1, Fig. 5 represents a box containing the battery and bell with the alarm suspended from the same, on a reduced scale.

The alarm consists of a cylindrical case 1 suspended from above, for instance by means of a tube 2 attached to the box 3 containing the battery and bell, or from the wall or ceiling. The battery and the bell may of course be placed wherever convenient or desired in another room than the one alarm is fixed in. The case 1 has a metal top 4L and metal bottom 5 between which the cylinder 6 of vulcanite or other suitable nonconductive material is fixed. The wires are led through the tube 2 and through the top A to which a disk 7 of wood or other nonconductive material is fixed. The wire S from one pole is conductively connected to the top 4L by means of a pin 8a, fixed therein as shown. The wire 9 from the other pole is connected to a metal plate 10 fixed to the disk 7. In this plate is fixed a wire or screw 11 passing through the bottom 5. A nut 12 on the screw serves to clamp the cylinder 6 between the top and bottom and to make a conductive connection between the wire 9 and the bottom 5. Additional means for screwing the cylinder to the ends may be provided. On the bottom 5 a ring 13 is formed or fixed having a central boss connected by arms 14C to the outer ring. In

Specification of Letters Patent.

Application filed. August 28, 1909.

Patented Sept. 12, 1911.

Serial No. 515,099.

this boss is fixed a stud 15 passing through a hole in a disk 16 of solid gelatin as commercially sold in sheets. Gelatin is a material which has a high co-eicient of expansion combined with a low co-efficient of heat conductivity. Above the disk a spider 17 of copper foil is held on the stud between collars 18 and 19. This spider is thus in conductive connection with the wire 9. Above the spider 17 at a short distance therefrom is arranged a ring 2O screwed to blocks 21, 22, 23, of leather, vulcanite or other con-conductive material, the blocks being xed to the bottom 5 by screws and the ring to these blocks so as to be insulated from the bottom. On the broad block 21 a bent metal angle plate 24C is clamped underneath the ring 20. Through the top A a screw 25 is threaded, preferably provided with a locknut 26 and carrying at the bottom a metal disk 27. Vhen this disk is pressed by the screw upon the edge of the angle plate 24 conductive connection is established between the ring 20 and the wire 8.

On the bottom 5 a tube 28 is arranged to which a shade or funnel 29 is attached for the purpose of conducting the heated air to the gelatin disk 16. The heat causes the central part of the gelatin disk 16, to expand, whereby it is rendered convex on its under side and the edge is raised and lifts the copper foil spider 17 or some of its legs against the underside of the ring 20, thereby closing the circuit and causing the alarm bell to be rung. A small rise of temperature sufhces to produce this nresult and the alarm is more sensitive than those employing the expansion of metal for eecting the closure of the circuit. By fixing the ring 2O at different distances from the gelatin disk 16 and spider 17, the temperature at which the alarm bell is rung can be determined.

I claim as my invent-ion:

1. In an'electric fire alarm the combination with a battery and an electric bell of a cylindrical casing having a non-conductive wall, a metal top conductively connected to one pole of said battery, and a metal bottom with a central opening and conductively connected to the other pole of the battery, a tube and funnel attached to said bottom at the opening, a disk of sheet gelatin above said opening, a copper foil spider above said disk and in conductive connection with the bottom of the casing, a metal ring supported on supports of non-conductive material fixed to said ring, and a Screw threaded through the top of the casing and carrying` a metal disk adapted to be screwed down upon said angle plate.

2. In an electric fire ala-rm the combination of a casing having a central opening inA ductor between said disk and ring forming the other terminal ot said circuit and adapted to be engaged by the outer part ol' said disk to be lifted by the same into Contact 1 with the said ring.

In testimony whereof I have hereunto set my hand in the presence of two witnesses. JACOB CASS. lVitnesses CARL BOLL, VILLIAM JONES.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 1). C. 

